For the securing of structures to cylindrical support elements, such as tubular foundation piles and the like, wedge devices are known, in which the load due to the weight of the structure produces on the wedges radial gripping forces permanently blocking the structure by friction onto the cylindrical element. An example of such an application is provided by the basement structures or decks of platforms for petroleum installations, which must be secured to the associated legs or foundation piles which provide their support.
Such basement structures or bridges, or other constructions for which such types of blocking devices are required are, in general, referred to below, in the interests of brevity, by the term "structures".
The known blocking devices have the characteristic of being rigid. Therefore, it is not possible, if necessary, to orientate the structure relative to the axis of the pile or column, for example in the case where the pile itself is not perfectly vertical, or where it may be necessary to arrange the structure or a part of it obliquely.
The known blocking devices, furthermore, are not easy to block and unblock, for example in the case where a modification of the position of the structure itself is required.
This renders assembly difficult in many cases, since it is often not possible to correct the position of the structure once it has been blocked on the pile. For orientation when it is possible, a lifting means for the structure, of the type used for positioning it, is required. The need for such a lifting means presents problems and incurs expense, especially in marine installations.
The inaccurate positioning of the structure on the piles, both with respect to elevation and with respect to the angle between the plane of the structure at the blocking point and the axis of the pile, is especially disadvantageous on account of the additional loads applied by it to the assembly. The correction of such inaccuracies during assembly is expensive and time-consuming.